This paper presents a new approach to the structural integration of piezoceramics into thin-walled steel components for condition-monitoring applications. The procedure for integrating the sensors into metal components is described, and their functionality is experimentally examined with a 2 mm-thick steel sheet. The signal quality of the produced sensors is investigated in a frequency range from 100 Hz to 50,000 Hz and is compared with the results of piezo patches and strain gauges under the same conditions. The results show that due to a higher signal-to-noise ratio and a better coherence, the structurally integrated piezoceramics and the piezo patches are more qualified sensors for vibration measurement in the examined frequency range than the strain gauges. The measurements also indicate that the patches provide higher amplitudes for the frequency range up to 20 kHz. Beyond that, up to 40 kHz, the integrated sensors supplied higher amplitudes. The better signal quality in different frequency ranges as well as the different manufacturing and application methods can be interpreted as an advantage or disadvantage depending on the boundary conditions of the condition-monitoring system. In summary, structural integrated piezoceramics extend the options of monitoring technology.

The importance of functional surfaces is continuously growing in the context of increasing demands on the sustainability of performance, resource efficiency and manufacturing costs of technical systems. For example, microstructured substrate surfaces can contribute to enhance the adhesion of layers, which in turn ensure the wear protection of a highly loaded component. Many microstructuring processes require a system change, entailing high costs. However, the ultrasonic vibration superimposed machining (UVSM) can be implemented as a finishing process. Due to its defined cutting-edge geometry and kinematics, UVSM represents a suitable method for a reliable generation of predefined surface microstructures. In order to optimize the process regarding the tool wear behavior and thus the geometrical characteristics of the surface microstructure, experimental investigations are carried out to find the most suitable combination of heat treatment condition of the martensitic stainless-steel X46Cr13 and various cutting materials. A vibration system for workpiece-side excitation is used for the experimental cutting tests. The most promising results were obtained within the combination of cemented carbide as a cutting tool and soft annealing as a heat treatment condition. They serve as a base for extensive investigations on the effects of substrate microstructuring to the adhesion of chemical vapor deposition (CVD) diamond layers to steel.

Magnetostrictive materials are a group of smart materials with comparable properties to piezoelectric materials regarding strain and operating frequency. In contrast, the Curie temperature is much higher and the principle effect allows different actuator designs. Especially in the case of rotating actuators in ultrasonic assisted machining, a high potential is seen for a simplified energy transmission. In the study, a test stand for a rotating actuator with simultaneous vibration in longitudinal direction was designed to show the proof of principle for this idea. It was shown that the current inducing the magnetic field as well as its frequency influence the amplitude of the rotating actuator. This is a first step to developing a rotating actuator for ultrasonic machining.

Magnetic shape memory alloys are a promising but rather novel smart material class. A test stand was developed and verified to characterize commercially available samples. The test stand generates a homogeneous magnetic field within the air gap when no sample is inserted. Once a Ni-Mn-Ga sample is inserted, the field remains homogeneous in the horizontal but not in the vertical direction. Rotating the sample around the long edge leads to a mirrored behavior. An FEM simulation based on the simplified description of the switching effect was built up. The simulation reproduced the experimental data principle but not in detail. The simplified description of the effect helps to understand the behavior of magnetic memory alloys, but for a deeper understanding micro-simulations with precise boundary conditions are necessary.